Methods and apparatuses for planarizing microelectronic substrate assemblies

ABSTRACT

Methods and apparatuses for planarizing microelectronic substrate assemblies on fixed-abrasive polishing pads with non-abrasive lubricating planarizing solutions. One aspect of the invention is to deposit a lubricating planarizing solution without abrasive particles onto a fixed-abrasive polishing pad having a body, a planarizing surface on the body, and a plurality of abrasive particles fixedly attached to the body at the planarizing surface. The front face of a substrate assembly is pressed against the lubricating planarizing solution and at least a portion of the fixed abrasive particles on the planarizing surface of the polishing pad. At least one of the polishing pad or the substrate assembly is then moved with respect to the other to impart relative motion therebetween. As the substrate assembly moves relative to the polishing pad, regions of the front face are separated from the abrasive particles in the polishing pad by a lubricant-additive in the lubricating planarizing solution.

TECHNICAL FIELD

[0001] The present invention relates to methods and apparatuses forplanarizing microelectronic substrate assemblies and, more particularly,to mechanical and/or chemical-mechanical planarization of such substrateassemblies using non-abrasive planarizing solutions and fixed-abrasivepolishing pads.

BACKGROUND OF THE INVENTION

[0002] Mechanical and chemical-mechanical planarizing processes(collectively “CMP”) are used in the manufacturing of electronic devicesfor forming a flat surface on semiconductor wafers, field emissiondisplays and many other microelectronic substrate assemblies. CMPprocesses generally remove material from a substrate assembly to createa highly planar surface at a precise elevation in the layers of materialon the substrate assembly.

[0003]FIG. 1 is a schematic isometric view of a web-format planarizingmachine 10 for planarizing a microelectronic substrate assembly 12. Theplanarizing machine 10 has a table 11 with a rigid panel or plate toprovide a flat, solid support surface 13 for supporting a portion of aweb-format planarizing pad 40 in a planarizing zone “A.” The planarizingmachine 10 also has a pad advancing mechanism including a plurality ofrollers to guide, position, and hold the web-format pad 40 over thesupport surface 13. The pad advancing mechanism generally includes asupply roller 20, first and second idler rollers 21 a and 21 b, firstand second guide rollers 22 a and 22 b, and a take-up roller 23. Asexplained below, a motor (not shown) drives the take-up roller 23 toadvance the pad 40 across the support surface 13 along a travel axisT-T. The motor can also drive the supply roller 20. The first idlerroller 21 a and the first guide roller 22 a press an operative portionof the pad against the support surface 13 to hold the pad 40 stationaryduring operation.

[0004] The planarizing machine 10 also has a carrier assembly 30 totranslate the substrate assembly 12 across the pad 40. In oneembodiment, the carrier assembly 30 has a head 32 to pick up, hold andrelease the substrate assembly 12 at appropriate stages of theplanarizing process. The carrier assembly 30 also has a support gantry34 and a drive assembly 35 that can move along the gantry 34. The driveassembly 35 has an actuator 36, a drive shaft 37 coupled to the actuator36, and an arm 38 projecting from the drive shaft 37. The arm 38 carriesthe head 32 via another shaft 39. The actuator 36 orbits the head 32about an axis B-B to move the substrate assembly 12 across the pad 40.

[0005] The polishing pad 40 may be a non-abrasive polymeric pad (e.g.,polyurethane), or it may be a fixed-abrasive polishing pad in whichabrasive particles are fixedly dispersed in a resin or another type ofsuspension medium. FIG. 2A, for example, is an isometric view of afixed-abrasive polishing pad having a body 41 including a backing film42 and a planarizing medium 43 on the backing film 42. The backing film42 can be a thin sheet of Mylar® Or other flexible, high-strengthmaterials. The abrasive planarizing medium 43 generally includes a resinbinder 44 and a plurality of abrasive particles 45 distributedthroughout the resin binder 44. The planarizing medium 43 is generallytextured to form a planarizing surface 46 having a plurality oftruncated pyramids, cylindrical columns, or other raised features. The3M Corporation of St. Paul, Minn., for example, manufactures severalfixed-abrasive polishing pads having alumina, ceria or other abrasiveparticles fixedly bonded to a Mylar® backing film 42 by a resin binder.

[0006] Referring again to FIG. 1, a planarizing fluid 50 flows from aplurality of nozzles 49 during planarization of the substrate assembly12. The planarizing fluid 50 may be a conventional CMP slurry withabrasive particles and chemicals that etch and/or oxidize the surface ofthe substrate assembly 12, or the planarizing fluid 50 may be a “clean”non-abrasive planarizing solution without abrasive particles. In mostCMP applications, abrasive slurries with abrasive particles are used onnon-abrasive polishing pads, and non-abrasive clean solutions withoutabrasive particles are used on fixed-abrasive polishing pads.

[0007] In the operation of the planarizing machine 10, the pad 40 movesacross the support surface 13 along the pad travel path T-T eitherduring or between planarizing cycles to change the particular portion ofthe polishing pad 40 in the planarizing zone A. For example, the supplyand take-up rollers 20 and 23 can drive the polishing pad 40 betweenplanarizing cycles such that a point P moves incrementally across thesupport surface 13 to a number of intermediate locations I₁, I₂, etc.Alternatively, the rollers 20 and 23 may drive the polishing pad 40between planarizing cycles such that the point P moves all the wayacross the support surface 13 to completely remove a used portion of thepad 40 from the planarizing zone A. The rollers may also continuouslydrive the polishing pad 40 at a slow rate during a planarizing cyclesuch that the point P moves continuously across the support surface 13.Thus, the polishing pad 40 should be free to move axially over thelength of the support surface 13 along the pad travel path T-T.

[0008] CMP processes should consistently and accurately produce auniform, planar surface on substrate assemblies to enable circuit anddevice patterns to be formed with photolithography techniques. As thedensity of integrated circuits increases, it is often necessary toaccurately focus the critical dimensions of the photo-patterns to withina tolerance of approximately 0.1 μm. Focusing photo-patterns to suchsmall tolerances, however, is difficult when the planarized surfaces ofsubstrate assemblies are not uniformly planar. Thus, to be effective,CMP processes should create highly uniform, planar surfaces on substrateassemblies.

[0009] The planarity of the finished substrate surface is a function ofseveral factors, one of which is the distribution of abrasive particlesunder the substrate assembly during planarization. In certainapplications that use a non-abrasive pad and an abrasive slurry, thedistribution of abrasive particles under the substrate assembly may notbe uniform because the edge of the substrate assembly wipes the slurryoff of the pad such that the center region of the substrate assemblydoes not consistently contact abrasive particles. The center region ofthe substrate assembly may accordingly have a different polishing ratethan the edge region causing a center-to-edge polishing gradient acrossthe substrate assembly.

[0010] Fixed abrasive polishing pads, like the one shown in FIG. 2A, arerelatively new and have the potential to produce highly planar surfaces.The primary technical advance of fixed-abrasive pads is that thedistribution of abrasive particles under the substrate assembly is not afunction of the distribution of the planarizing solution because theabrasive particles are fixedly attached to the pad. Fixed abrasive padsaccordingly provide a more uniform distribution of abrasive particlesunder the substrate assembly 12 than abrasive slurries on non-abrasivepads. Fixed-abrasive polishing pads, however, may scratch or otherwiseproduce defects on the finished substrate surface. The particularmechanism that causes scratching and defects is not completelyunderstood, but it is expected that large pieces 47 of thefixed-abrasive planarizing medium 43 (see FIG. 2) break away duringplanarization and scratch the substrate assembly 12. Fixed-abrasive padsmay also produce defects because, unlike abrasive slurries in which theabrasive particles are mobile and can move with the slurry, the abrasiveparticles in fixed-abrasive pads do not roll or move with the substrateassembly. As such, minor peaks on the raised features of the planarizingsurface 46 or disparities in the size or shape of the fixed-abrasiveparticles 45 may scratch the substrate surface. Therefore, even thoughfixed-abrasive pads are promising, they may scratch the finishedsubstrate surface of microelectronic substrate assemblies or otherwiseproduce defects in the integrated circuits.

SUMMARY OF THE INVENTION

[0011] The present invention relates to planarizing microelectronicsubstrate assemblies on fixed-abrasive polishing pads with non-abrasiveplanarizing solutions. One aspect of the invention is to deposit alubricating planarizing solution without abrasive particles onto afixed-abrasive polishing pad having a body, a planarizing surface on thebody, and a plurality of abrasive particles fixedly attached to the bodyat the planarizing surface. The front face of a substrate assembly ispressed against the lubricating planarizing solution and at least aportion of the planarizing surface of the polishing pad. At least one ofthe polishing pad or the substrate assembly is then moved with respectto the other to impart relative motion therebetween. As the substrateassembly moves relative to the polishing pad, regions of the front faceare separated from the abrasive particles in the polishing pad by alubricant-additive in the planarizing solution.

[0012] In one particular application, separating the regions of thefront face of the substrate assembly from the abrasive particlesinvolves dissolving the lubricant-additive into a non-abrasive solutionto form the lubricating planarizing solution, and then depositing thelubricating planarizing solution onto the polishing pad as the substrateassembly moves relative to the polishing pad. The lubricant-additive canbe glycerol, polyethylene glycol, polypropylene glycol, CARBOGELmanufactured by B.F. Goodrich, polyvinyl alcohol, POLYOX manufactured byUnion Carbide, or some other lubricating liquid. The concentration ofthe lubricant-additive in the non-abrasive solution is selected so thatthe lubricating planarizing solution has a viscosity of at leastapproximately 4-100 cp, and more generally 10-20 cp. In operation, thelubricating planarizing solution provides a protective boundary layerbetween the front face of the substrate assembly and the abrasiveplanarizing surface to inhibit the fixed abrasive particles from overlyabrading the substrate assembly. Thus, compared to planarizing solutionswithout the lubricant-additive, the lubricating planarizing solution isexpected to reduce defects and scratches on the front face of thesubstrate assembly in fixed-abrasive planarization.

BRIEF DESCRIPTION OF THE DRAWINGS

[0013]FIG. 1 is a schematic isometric view of a planarizing machine inaccordance with the prior art.

[0014]FIG. 2 is a partial isometric view of a fixed-abrasive polishingpad in accordance with the prior art.

[0015]FIG. 3 is a schematic isometric view of a web-format planarizingmachine used in accordance with an embodiment of the invention.

[0016]FIG. 4 is a schematic cross-sectional view of a lubricatingplanarizing solution further illustrating methods in accordance with anembodiment of the invention.

DETAILED DESCRIPTION OF THE INVENTION

[0017] The present invention relates to planarizing microelectronicsubstrate assemblies on fixed-abrasive polishing pads with non-abrasivelubricating planarizing solutions. Several aspects and details ofcertain embodiments of this invention are described in detail below, andillustrated in FIGS. 3 and 4, to provide a thorough understanding ofmaking and using these embodiments of the invention. It will beappreciated, however, that particular details may be omitted from someof the embodiments, or that there may be additional embodiments of theinvention that are covered by the following claims.

[0018]FIG. 3 is a schematic isometric view of a web-format planarizingmachine 100 for planarizing a microelectronic substrate assembly 12 inaccordance with an embodiment of the invention. The planarizing machine100 includes a table 111 having a support surface 113, a carrierassembly 130 over the table 111, and a polishing pad 140 on the supportsurface 113. The table 111, support surface 113 and carrier assembly 130can be substantially the same as those described above with reference toFIG. 1. The polishing pad 140 is coupled to a pad advancing mechanismhaving a plurality of rollers 120, 121 a, 121 b, 122 a, 122 b and 123.The pad advancing mechanism can also be the same as that described abovewith reference to FIG. 1. The planarizing machine 100 further includes afirst container 110 holding a supply of a non-abrasive solution 150 anda second container 112 holding a supply of a lubricant-additive 160.

[0019] The non-abrasive solution 150 can be an aqueous planarizingsolution containing water, oxidants, surfactants, and other non-abrasivematerials. The non-abrasive solution 150 does not contain abrasiveparticles that are commonly used in abrasive CMP slurries (e.g.,alumina, ceria, titania, titanium, silica or other abrasive particles).For example, the non-abrasive solution 150 can contain water and eitherammonia or potassium hydroxide. The non-abrasive solution 150, morespecifically, can include 65-99.9% of deionized water and 0.1-35% ofeither NH₄OH, NH₄NO₃, NH₄Cl or KOH. The non-abrasive solution 150 alsogenerally has a viscosity of 1.0-2.0 cp and a pH of 2.0-13.5, andgenerally a pH of 9.0-13.0. In general, the non-abrasive solution 150 isselected to etch and/or oxidize the materials at the surface of thesubstrate assembly 12. The non-abrasive solution 150, therefore, mayhave compositions other than water and either ammonia or potassiumhydroxide.

[0020] The lubricant-additive 160 is a separate solution or dry chemicalcompound that increases the viscosity of the non-abrasive solution 150without altering the chemical effects of the non-abrasive solution 150on the substrate assembly 12 during planarization. Thelubricant-additive 160 can be glycerol, polyethylene glycol,polypropylene glycol, polyvinyl alcohol, CARBOGEL® manufactured by B.F.Goodrich, or POLYOX® manufactured by Union Carbide. It will beappreciated that the lubricant-additive 160 may be composed of otherlubricants suitable for contact with the substrate assembly 12.

[0021] The lubricant-additive 160 is combined with the non-abrasivesolution 150 to make a lubricating planarizing solution 170. Theconcentration of the lubricant-additive 160 in the non-abrasive solution150 is generally selected so that the lubricating planarizing solution170 has a viscosity of at least approximately 4-100 cp, and morepreferably 10-20 cp. The particular composition of the lubricatingplanarizing solution 170 will generally depend, at least in part, uponthe type of abrasive particles in the pad, the shape of the raisedfeatures on the pad, and the types of material on the substrate assembly12. The lubricating planarizing solution 170 can include the followingranges of non-abrasive solution 150 and lubricant-additive 160: (A)90%-99.9% ammonia and water, and 0.1-10% POLYOX or CARBOGEL; or (B)80%-95% ammonia and water, and 5-20% glycerol, polyethylene glycol orpolypropylene glycol. The following compositions of lubricatingplanarizing solutions 170 are thus offered by way of example, notlimitation: COMPOSITION 1 0.25% weight POLYOX 99.75% weight NH₄OH—H₂O orKOH—H₂O Solution with a pH of approximately 10-11 COMPOSITION 2 10%weight Glycerol 90% weight NH₄OH—H₂O or KOH—H₂O Solution COMPOSITION 310% weight Polyethylene Glycol 90% weight NH₄OH—H₂O or KOH—H₂O SolutionCOMPOSITION 4 5% weight Polypropylene Glycol 95% weight NH₄OH—H₂O orKOH—H₂O Solution COMPOSITION 5 0.25% weight CARBOGEL 99.75% weightNH₄OH—H₂O or KOH—H₂O Solution

[0022] The lubricating planarizing solution 170 can be fabricated bymixing the lubricant-additive 160 with the non-abrasive solution 150 ata mixing site 114. The mixing site 114 generally provides turbulence toadmix the non-abrasive solution 150 and the lubricant-additive 160. Themixing site 114, for example, can be a separate tank with an agitator(not shown), or the mixing site 114 can be a joint or an elbow in a lineconnecting the first container 110 to the second container 112. Themixing site 114 is coupled to the carrier head 132 by a conduit 115 todeliver the lubricating planarizing solution 170 to the nozzles 149 ofthe carrier head 132. The conduit 115 can be similar to those used todeliver abrasive planarizing slurries or non-abrasive planarizingsolutions without lubricant-additives to web-format or rotaryplanarizing machines.

[0023]FIG. 4 is a schematic cross-sectional view of the substrateassembly 12 being planarized on a fixed-abrasive polishing pad 40 withthe lubricating planarizing solution 170. The fixed-abrasive polishingpad 40 can be substantially the same as the pad 40 described above withreference to FIG. 2, and thus like reference numbers refer to likecomponents. In operation, the lubricating planarizing solution 170provides a protective boundary layer 172 between the front face 15 ofthe substrate assembly and the abrasive planarizing surface 46 at thetop of the raised features. The boundary layer 172 of planarizingsolution 170 separates regions of the front face 15 from the planarizingsurface 46 to inhibit the fixed-abrasive particles 45 from overlyabrading the front face 15. Thus, compared to planarizing solutionswithout the lubricant-additive 160, the lubricating planarizing solution170 with the lubricant-additive 160 is expected to reduce defects andscratches on the front face 15 of the substrate assembly 12 infixed-abrasive CMP processing.

[0024] From the foregoing it will be appreciated that, although specificembodiments of the invention have been described herein for purposes ofillustration, various modifications may be made without deviating fromthe spirit and scope of the invention. For example, the process may beimplemented using a rotary planarizing machine. Suitable rotaryplanarizing machines are manufactured by Applied Materials, Inc.,Westech Corporation, and Strasbaugh Corporation, and suitable rotaryplanarizing machines are described in U.S. Pat. Nos. 5,456,627;5,486,131; and 5,792,709, which are herein incorporated by reference.Accordingly, the invention is not limited except as by the appendedclaims.

1. A method of planarizing a microelectronic-device substrate assembly,comprising: depositing a lubricating planarizing solution withoutabrasive particles onto a polishing pad, the polishing pad having abody, a planarizing surface on the body, and a plurality of abrasiveparticles fixedly attached to the body at the planarizing surface;pressing a front face of the substrate assembly against the lubricatingplanarizing solution and at least a portion of the fixed abrasiveparticles on the planarizing surface; moving at least one of thepolishing pad or the substrate assembly with respect to the other toimpart relative motion therebetween; and separating regions of the frontface from the abrasive particles with a lubricant-additive in thelubricating planarizing solution as the substrate assembly movesrelative to the polishing pad.
 2. The method of claim 1 whereindepositing the lubricating solution comprises: adding thelubricant-additive into a non-abrasive solution to form the lubricatingplanarizing solution; and disposing the lubricating planarizing solutionwith the added lubricant-additive onto the polishing pad as thesubstrate assembly moves relative to the polishing pad.
 3. The method ofclaim 1 wherein depositing the lubricating solution comprises mixing thelubricant-additive into a non-abrasive solution to form a lubricatingplanarizing solution having a viscosity of at least approximately 10-20cp and disposing the lubricating planarizing solution onto the polishingpad as the substrate assembly moves relative to the polishing pad. 4.The method of claim 1 wherein: the lubricant-additive comprisesglycerol; and depositing the lubricating solution comprises mixing theglycerol into a non-abrasive solution comprising ammonia and water toform a lubricating planarizing solution having a viscosity of at leastapproximately 4-20 cp, and disposing the lubricating planarizingsolution onto the polishing pad as the substrate assembly moves relativeto the polishing pad.
 5. The method of claim 1 wherein: thelubricant-additive comprises glycerol; and depositing the lubricatingsolution comprises mixing 10% by weight of the glycerol into 90% byweight of a non-abrasive solution comprising ammonia and water to formthe lubricating planarizing solution, and disposing the lubricatingplanarizing solution onto the polishing pad as the substrate assemblymoves relative to the polishing pad.
 6. The method of claim 1 wherein:the lubricant-additive comprises polypropylene glycol; and depositingthe lubricating solution comprises mixing the polypropylene glycol intoa non-abrasive solution comprising ammonia and water to form alubricating planarizing solution having a viscosity of at leastapproximately 4-20 cp, and disposing the lubricating planarizingsolution onto the polishing pad as the substrate assembly moves relativeto the polishing pad.
 7. The method of claim 1 wherein: thelubricant-additive comprises polypropylene glycol; and depositing thelubricating solution comprises mixing 5% by weight of the polypropyleneglycol into 95% by weight of a non-abrasive solution comprising ammoniaand water to form the lubricating planarizing solution, and disposingthe lubricating planarizing solution onto the polishing pad as thesubstrate assembly moves relative to the polishing pad.
 8. The method ofclaim 1 wherein: the lubricant-additive comprises polyethylene glycol;and depositing the lubricating solution comprises mixing thepolyethylene glycol into a non-abrasive solution comprising ammonia andwater to form a lubricating planarizing solution having a viscosity ofat least approximately 4-20 cp, and disposing the lubricatingplanarizing solution onto the polishing pad as the substrate assemblymoves relative to the polishing pad.
 9. The method of claim 1 wherein:the lubricant-additive comprises polyethylene glycol; and depositing thelubricating solution comprises mixing 10% by weight of the polyethyleneglycol into 90% by weight of a non-abrasive solution comprising ammoniaand water to form the lubricating planarizing solution and disposing thelubricating planarizing solution onto the polishing pad as the substrateassembly moves relative to the polishing pad.
 10. The method of claim 1wherein: the lubricant-additive comprises polyvinyl alcohol; anddepositing the lubricating solution comprises mixing the polyvinylalcohol into a non-abrasive solution comprising ammonia and water toform a lubricating planarizing solution having a viscosity of at leastapproximately 4-100 cp, and disposing the lubricating planarizingsolution onto the polishing pad as the substrate assembly moves relativeto the polishing pad.
 11. The method of claim 1 wherein: thelubricant-additive comprises polyvinyl alcohol; and depositing thelubricating solution comprises mixing 10% by weight of the polyvinylalcohol into 90% by weight of a non-abrasive solution comprising ammoniaand water to form the lubricating planarizing solution, and disposingthe lubricating planarizing solution onto the polishing pad as thesubstrate assembly moves relative to the polishing pad.
 12. The methodof claim 1 wherein: the lubricant-additive comprises CARBOGEL; anddepositing the lubricating solution comprises mixing the CARBOGEL into anon-abrasive solution comprising ammonia and water to form a lubricatingplanarizing solution having a viscosity of at least approximately 4-100cp, and disposing the lubricating planarizing solution onto thepolishing pad as the substrate assembly moves relative to the polishingpad.
 13. The method of claim 1 wherein: the lubricant-additive comprisesCARBOGEL; and depositing the lubricating solution comprises mixing 0.25%by weight of the CARBOGEL into 99.75% by weight of a non-abrasivesolution comprising ammonia and water to form the lubricatingplanarizing solution, and disposing the lubricating planarizing solutiononto the polishing pad as the substrate assembly moves relative to thepolishing pad.
 14. The method of claim 1 wherein: the lubricant-additivecomprises POLYOX; and depositing the lubricating solution comprisesmixing the POLYOX into a non-abrasive solution comprising ammonia andwater to form a lubricating planarizing solution having a viscosity ofat least approximately 4-100 cp, and disposing the lubricatingplanarizing solution onto the polishing pad as the substrate assemblymoves relative to the polishing pad.
 15. The method of claim 1 wherein:the lubricant-additive comprises POLYOX; and depositing the lubricatingsolution comprises mixing 0.25% by weight of the POLYOX into 99.75% byweight of a non-abrasive solution comprising ammonia and water to formthe lubricating planarizing solution, and disposing the lubricatingplanarizing solution onto the polishing pad as the substrate assemblymoves relative to the polishing pad.
 16. A method of planarizing amicroelectronic-device substrate assembly comprising: depositing alubricating planarizing solution without abrasive particles onto apolishing pad, the lubricating planarizing solution having a lubricantadditive, and the polishing pad having a body, a planarizing surface onthe body, and abrasive particles fixedly attached to the body at theplanarizing surface; pressing a front face of the substrate assemblyagainst the planarizing solution on the planarizing surface; and movingat least one of the polishing pad or the substrate assembly with respectto the other to impart relative motion between the front face of thesubstrate assembly and the planarizing surface.
 17. The method of claim16 wherein: the lubricant-additive comprises a viscosity-increasingagent that increases the viscosity of the planarizing solution; and themethod further comprises mixing the viscosity-increasing agent into anon-abrasive solution to form the lubricating planarizing solution priorto depositing the lubricating planarizing solution onto the polishingpad.
 18. The method of claim 17 wherein: the viscosity-increasing agentcomprises glycerol; and mixing the viscosity-increasing agent into thenon-abrasive solution comprises mixing the glycerol into a non-abrasivesolution comprising ammonia and water to form a lubricating planarizingsolution having a viscosity of at least approximately 4-20 cp.
 19. Themethod of claim 17 wherein: the viscosity-increasing agent comprisespolypropylene glycol; and mixing the viscosity-increasing agent into thea non-abrasive solution comprises mixing the polypropylene glycol into anon-abrasive solution comprising ammonia and water to form a lubricatingplanarizing solution having a viscosity of at least approximately 4-20cp.
 20. The method of claim 17 wherein: the viscosity-increasing agentcomprises polyethylene glycol; and mixing the viscosity-increasing agentinto the non-abrasive solution comprises mixing the polyethylene glycolinto a non-abrasive solution comprising ammonia and water to form alubricating planarizing solution having a viscosity of at leastapproximately 4-20 cp.
 21. The method of claim 17 wherein: theviscosity-increasing agent comprises polyvinyl alcohol; and mixing theviscosity-increasing agent into the non-abrasive solution comprisesmixing the polyvinyl alcohol into a non-abrasive solution comprisingammonia and water to form a lubricating planarizing solution having aviscosity of at least approximately 4-100 cp.
 22. The method of claim 17wherein: the viscosity-increasing agent comprises CARBOGEL; and mixingthe viscosity-increasing agent into the non-abrasive solution comprisesmixing the CARBOGEL into a non-abrasive solution comprising ammonia andwater to form a lubricating planarizing solution having a viscosity ofat least approximately 4-100 cp.
 23. The method of claim 17 wherein: theviscosity-increasing agent comprises POLYOX; and mixing theviscosity-increasing agent into the non-abrasive solution comprisesmixing the POLYOX into a non-abrasive solution comprising ammonia andwater to form a lubricating planarizing solution having a viscosity ofat least approximately 4-100 cp.
 24. A method of planarizing amicroelectronic-device substrate assembly comprising: depositing anon-abrasive solution without abrasive particles onto a polishing pad,the polishing pad having a body, a planarizing surface on the body, anda plurality of abrasive particles fixedly attached to the body at theplanarizing surface; pressing a front face of the substrate assemblyagainst the non-abrasive solution and the planarizing surface; moving atleast one of the polishing pad or the substrate assembly with respect tothe other to impart relative motion between the front face of thesubstrate assembly and the planarizing surface; and inhibiting the fixedabrasive particles attached to the pad from aggressively abrading thefront face and causing defects on the substrate assembly by adding ahigh viscosity substance to the non-abrasive solution to form alubricating planarizing solution.
 25. The method of claim 24 wherein:the high viscosity substance comprises glycerol; and adding a highviscosity substance to the non-abrasive solution comprises mixing theglycerol into a non-abrasive solution comprising ammonia and water toform a lubricating planarizing solution having a viscosity of at leastapproximately 4-20 cp.
 26. The method of claim 25 wherein: the highviscosity substance comprises polypropylene glycol; and adding a highviscosity substance to the non-abrasive solution comprises mixing thepolypropylene glycol into a non-abrasive solution comprising ammonia andwater to form a lubricating planarizing solution having a viscosity ofat least approximately 4-20 cp.
 27. The method of claim 25 wherein: thehigh viscosity substance comprises polyethylene glycol; and adding ahigh viscosity substance to the non-abrasive solution comprises mixingthe polyethylene glycol into a non-abrasive solution comprising ammoniaand water to form a lubricating planarizing solution having a viscosityof at least approximately 4-20 cp.
 28. The method of claim 24 wherein:the high viscosity substance comprises polyvinyl alcohol; and adding ahigh viscosity substance to the non-abrasive solution comprises mixingthe polyvinyl alcohol into a non-abrasive solution comprising ammoniaand water to form a lubricating planarizing solution having a viscosityof at least approximately 4-100 cp.
 29. The method of claim 24 wherein:the high viscosity substance comprises CARBOGEL; and adding a highviscosity substance to the non-abrasive solution comprises mixing theCARBOGEL into a non-abrasive solution comprising ammonia and water toform a lubricating planarizing solution having a viscosity of at leastapproximately 4-100 cp.
 30. The method of claim 24 wherein: the highviscosity substance comprises POLYOX; and adding a high viscositysubstance to the non-abrasive solution comprises mixing the POLYOX intoa non-abrasive solution comprising ammonia and water to form alubricating planarizing solution having a viscosity of at leastapproximately 4-100 cp.
 31. A method of planarizing amicroelectronic-device substrate assembly comprising: providing apolishing pad having a body, a planarizing surface on the body, and aplurality of abrasive particles fixedly attached to the body at theplanarizing surface; depositing a non-abrasive lubricating planarizingsolution without abrasive particles onto the polishing pad having aviscosity of at least approximately 10-20 cp; pressing a front face ofthe substrate assembly against the planarizing solution on theplanarizing surface; and moving at least one of the polishing pad or thesubstrate assembly with respect to the other to impart relative motionbetween the front face of the substrate assembly and the planarizingsurface.
 32. The method of claim 31 , further comprising: providing anon-abrasive solution without abrasive particles containing at leastwater; and adding a lubricant-additive to the non-abrasive solution toform the non-abrasive lubricating solution without abrasive particles.33. The method of claim 31 , further comprising forming the lubricatingplanarizing solution by mixing glycerol into a non-abrasive solutioncomprising ammonia and water until the lubricating planarizing solutionhas a viscosity of at least approximately 4-20 cp.
 34. The method ofclaim 31 , further comprising forming the lubricating planarizingsolution by mixing polypropylene glycol into a non-abrasive solutioncomprising ammonia and water until the lubricating planarizing solutionhas a viscosity of at least approximately 4-20 cp.
 35. The method ofclaim 31 , further comprising forming the lubricating planarizingsolution by mixing polyethylene glycol into a non-abrasive solutioncomprising ammonia and water until the lubricating planarizing solutionhas a viscosity of at least approximately 4-20 cp.
 36. The method ofclaim 31 , further comprising forming the lubricating planarizingsolution by mixing polyvinyl alcohol into a non-abrasive solutioncomprising ammonia and water until the lubricating planarizing solutionhas a viscosity of at least approximately 4-100 cp.
 37. The method ofclaim 31 , further comprising forming the lubricating planarizingsolution by mixing CARBOGEL into a non-abrasive solution comprisingammonia and water until the lubricating planarizing solution has aviscosity of at least approximately 4-100 cp.
 38. The method of claim 31, further comprising forming the lubricating planarizing solution bymixing POLYOX into a non-abrasive solution comprising ammonia and wateruntil the lubricating planarizing solution has a viscosity of at leastapproximately 4-100 cp.
 39. A method of making a lubricating planarizingsolution, comprising: providing a non-abrasive solution without abrasiveparticles containing at least water; and adding a lubricant-additive tothe non-abrasive solution to form a non-abrasive lubricating planarizingsolution without abrasive particles.
 40. The method of claim 39 whereinadding the lubricant-additive to the non-abrasive solution comprisingmixing the lubricant additive with the non-abrasive solution until thelubricating planarizing solution has a viscosity of at leastapproximately 4 cp.
 41. The method of claim 39 wherein adding thelubricant-additive to the non-abrasive solution comprising mixingglycerol with a non-abrasive solution comprising water and ammonia toform a lubricating planarizing solution having a viscosity of at least 4cp.
 42. The method of claim 39 wherein adding the lubricant-additive tothe non-abrasive solution comprising mixing polypropylene glycol with anon-abrasive solution comprising water and ammonia to form a lubricatingplanarizing solution having a viscosity of at least 4 cp.
 43. The methodof claim 39 wherein adding the lubricant-additive to the non-abrasivesolution comprising mixing polyethylene glycol with a non-abrasivesolution comprising water and ammonia to form a lubricating planarizingsolution having a viscosity of at least 4 cp.
 44. The method of claim 39wherein adding the lubricant-additive to the non-abrasive solutioncomprising mixing polyvinyl alcohol with a non-abrasive solutioncomprising water and ammonia to form a lubricating planarizing solutionhaving a viscosity of at least 10 cp.
 45. The method of claim 39 whereinadding the lubricant-additive to the non-abrasive solution comprisingmixing CARBOGEL with a non-abrasive solution comprising water andammonia to form a lubricating planarizing solution having a viscosity ofat least 10 cp.
 46. The method of claim 39 wherein adding thelubricant-additive to the non-abrasive solution comprising mixing POLYOXwith a non-abrasive solution comprising water and ammonia to form alubricating planarizing solution having a viscosity of at least 10 cp.47. The method of claim 39 wherein adding the lubricant-additive to thenon-abrasive solution comprises mixing approximately 10% by weight ofglycerol with approximately 90% by weight of a non-abrasive solutionincluding water and ammonia.
 48. The method of claim 39 wherein addingthe lubricant-additive to the non-abrasive solution comprises mixingapproximately 5% by weight of polypropylene glycol with approximately95% by weight of a non-abrasive solution including water and ammonia.49. The method of claim 39 wherein adding the lubricant-additive to thenon-abrasive solution comprises mixing approximately 10% by weight ofpolyethylene glycol with approximately 90% by weight of a non-abrasivesolution including water and ammonia.
 50. The method of claim 39 whereinadding the lubricant-additive to the non-abrasive solution comprisesmixing approximately 10% by weight of polyvinyl alcohol withapproximately 90% by weight of a non-abrasive solution including waterand ammonia.
 51. The method of claim 39 wherein adding thelubricant-additive to the non-abrasive solution comprises mixingapproximately 0.25% by weight of CARBOGEL with approximately 99.75% byweight of a non-abrasive solution including water and ammonia.
 52. Themethod of claim 39 wherein adding the lubricant-additive to thenon-abrasive solution comprises mixing approximately 0.25% by weight ofPOLYOX with approximately 99.75% by weight of a non-abrasive solutionincluding water and ammonia.
 53. A lubricating planarizing solution,comprising: a non-abrasive solution without abrasive particles, thenon-abrasive solution having a viscosity less than 4 cp; and alubricant-additive mixed with the non-abrasive solution, thelubricant-additive being a non-abrasive compound having a viscositygreater than approximately 4 cp, wherein the lubricating planarizingsolution does not include abrasive particles and has a viscosity atleast greater than 4 cp.
 54. The lubricating planarizing solution ofclaim 53 wherein: the non-abrasive solution comprises water and ammonia;and the lubricant additive comprises glycerol.
 55. The lubricatingplanarizing solution of claim 53 wherein: the non-abrasive solutioncomprises water and ammonia; and the lubricant additive comprisespolypropylene glycol.
 56. The lubricating planarizing solution of claim53 wherein: the non-abrasive solution comprises water and ammonia; andthe lubricant additive comprises polyethylene glycol.
 57. Thelubricating planarizing solution of claim 53 wherein: the non-abrasivesolution comprises water and ammonia; and the lubricant additivecomprises polyvinyl alcohol.
 58. The lubricating planarizing solution ofclaim 53 wherein: the non-abrasive solution comprises water and ammonia;and the lubricant additive comprises CARBOGEL.
 59. The lubricatingplanarizing solution of claim 53 wherein: the non-abrasive solutioncomprises water and ammonia; and the lubricant additive comprisesPOLYOX.
 60. A planarizing machine for planarizing microelectronic-devicesubstrate assemblies, comprising: a support table; a polishing pad onthe support table, the polishing pad having a body, a planarizingsurface on the body, and a plurality of abrasive particles fixedlyattached to the body at the planarizing surface; a carrier assemblyhaving a carrier head configured to hold a substrate assembly and adrive mechanism attached to the carrier head to move the carrierrelative to the polishing pad; and a non-abrasive lubricatingplanarizing solution without abrasive particles on the polishing pad,the lubricating planarizing solution having a viscosity of at leastapproximately 4-100 cp.
 61. A planarizing machine for planarizingmicroelectronic-device substrate assemblies, comprising: a supporttable; a polishing pad on the support table, the polishing pad having abody, a planarizing surface on the body, and a plurality of abrasiveparticles fixedly attached to the body at the planarizing surface; acarrier assembly having a carrier head configured to hold a substrateassembly and a drive mechanism attached to the carrier head to move thecarrier relative to the polishing pad; a first container and a supply ofa non-abrasive solution in the first container; a second container and asupply of a lubricant-additive in the second container; and a mixingsite coupled to the first and second containers, the lubricant additivebeing mixed with non-abrasive solution at the mixing site to produce alubricating planarizing solution, and the mixing site being coupled to anozzle to dispense the lubricating planarizing solution onto thepolishing pad.